1. Field of the Invention
The present invention relates to a filament winding apparatus that manufactures products such as hollow containers or the like by winding fiber bundles unwound from fiber bundle feeding packages around a mandrel and, in particular, to a tension control system that controls a tension of the fiber bundles, predicts fiber bundle breakage, and prevents the generation of defective products.
2. Description of the Related Art
As is commonly known, a filament winding apparatus manufactures products including hollow containers such as pressure containers and pipes, for example, by winding fiber bundles R around a mandrel (liner). In the present invention, the fiber bundle R is made by twisting a plurality of single fibers f into one filament yarn as illustrated in FIG. 11A. In the filament winding apparatus, a prescribed winding tension is applied to the fiber bundles R unwound from fiber bundle feeding packages, and the fiber bundles R run in a tension-applied state and then are wound around a mandrel M.
A conventional filament winding apparatus as described in JP 2007-260974A, for example, includes a configuration in which a tension of fiber bundles F is controlled.
As illustrated in FIG. 2 of JP2007-260974A, in a conventional filament winding apparatus 11, a plurality of bobbins B having the fiber bundles F wound around are supported by a spindle 12b connected with a creel stand 12a. By applying a load to rotation of the spindle 12b, the creel stand 12a functions as a tension applying member that applies a winding tension to the fiber bundles F unwound from the bobbins B. The winding tension of the fiber bundles F is measured in a pathway of the fiber bundles F by a tension measuring unit 21 provided on a downstream side of the tension applying member. A control unit 30 controls the load applied to the rotation of the spindle 12b in accordance with the output from the tension measuring unit 21 and thus adjusts the winding tension of the fiber bundles F to a proper value.
In the above conventional filament winding apparatus, the fiber bundles often break in midstream for some reasons. In such a conventional filament winding apparatus, the “fiber bundle breakage” is detected by a configuration such as that described in JP 2003-206071A, for example.
As illustrated in FIG. 1 of JP 2003-206071A, in a conventional filament winding apparatus, an area sensor 4 is provided in a space between a winding unit 1 and a supply unit 10, slightly closer to the winding unit 1. In the apparatus, when a yarn (fiber bundle) F is tensioned in a normal state, the yarn F passes above a detection area of the area sensor 4. To the contrary, when the yarn F breaks for some reasons, the yarn F droops and comes in the detection area of the area sensor 4. Having detected such invasion of the yarn F, the area sensor 4 notifies an operator of the yarn breakage via a speaker or a display, or the like, and stops the filament winding apparatus.
However, the filament winding apparatus described in JP 2003-206071A can only detect complete breakage of the fiber bundle F, and cannot detect a high probability of fiber bundle breakage. Accordingly, in the conventional technique described in JP 2003-206071A, although the filament winding apparatus is stopped when the fiber bundle breakage is detected, the product that is being manufactured at the time of fiber bundle breakage becomes defective and has to be discarded.